Electronic timer



Nov. 19, 1935. M'. E. BIVENS ELECTRONIC TIMER Filed June 28, 1934 5Sheets-Sheet 1 FigJ.

Inventor: Maurice EBivens.

X7 (f-fiumiam His ttor'nezg.

Nov. 19, 1935. M, E BWEN 2,021,766

ELECTRONIC TIMER Filed June 28, 1954 5 Sheeis-Sheet 2 2 l8 oPEFAnouRESET Inventor.

Maurice E. Bivens.

HIS Abborne u Nov. 1 1935.

M. E. BIVENS ELECTRONIC TIMER Filed June 28, 1934 5 Sheets-Sheet 5 V Y eWW m mm WIS Hm WNH Nov. 19, 1935. M, E, BNEN 2,021,766

ELECTRONIC TIMER Filed June 28, 1954 5 SheetsSheet 4 57 58 Hi F210 '77 OA n 27 6%; as Y 7 J L3 L4 as 55 L La .51?

fayig -19 I2, 76

Irfiventor:

Maurice E. BiVeF-WS,

Nov. 19, 1935. M. E. BIVENS ELECTRONIC TIMER Filed June 28, 1934 5Sheets-Sheet 5 Fig. l5.

Inventor" Maurice IiBivens,

by His Attorney,

Patented Now-19,1935

UNITED STATES ELECTRONIC rm Maurice E. Bivens, Media, Pa., assignortoGeneral Electric Company, a corporation of New York Application Juneas, 1934, Serial No. 732,827

16 Claims. (01. 175-183) My invention relates to timing devices andconcerns particularly electronic timers for checking relay operations.

It is an object of my invention to provide an inertialess device formeasuring extremely short, as well as longer, intervals of timewithaccuracy.

It is a further object of my invention to provide a device which may beset.for measuring not merely the time interval between the opening andclosing of an electrical contact or vice versa but also the timeinterval between the opening or closing of one electrical contact andthe opening or closing of another electrical contact.

The objects of my invention include providing a relay timer formeasuring both total time, open or closed, as well as the operating timeof either normally-open or normally-closed relays either when energizedor when deenergized.

Other and further objects and advantages will become apparent as thedescription proceeds.

In accordance with my invention in its preferred form, I determine thetime required for the consummation of an operation by determine ing theamount of charge supplied to a timing condenser through aconstant-current circuit during the operation. Preferably, I supplyinertialess means, such as grid-controlled discharge tubes, forcontrolling the starting and stopping of the charging current at thebeginning and the end of an operation to be measured. The

discharge tubes are connected in parallel circuits with resistors intheir anode leads or source of current. Current is initiated in one tubeat the beginning of a time interval to be measured and shifted to theother at the end of the interval by controlling potential of the controlgrids in response to operations to be timed. In consequence, a potentialdifference is built up and then reversed between the tube anodes. Atiming condenser in series with a constant-current rectifier isconnected between the anodes of the discharge tubes and receivescharging current only during the time interval. The voltage acquired bythe timing condenser is compared with; a measurable voltage to determinethe. length' of the time interval. Changeable connections are providedto permit connecting a relay to be tested in the apparatus in difierentways with respect to the control grids of the tubes for the purpose ofchecking different types of relay operations.

The features of my invention which I believe to be novel and patentablewill be pointed out in the claims appended hereto. A betterunderstanding of myinvention, itself, however, may be obtained byreferring to the following description taken in connection with theaccompanying drawings- I Fig. 1 of the drawings is a circuit diagram ofan embodiment of my invention; Fig. 2 is a simplified diagram of aportion of the apparatus of 5 Fig. 1 showing the circuit made when theapparatus is set for adjusting the charging current of the timingcondenser; Fig. 3 is a symbolic op:- eration diagram showing the mannerin which the apparatus is manipulated to obtain the cirl0 cuit of Fig. 2and to adjust the condenser-charging current; Fig. 4 is a simplifiedcircuit diagram of the apparatus set for testing theclosing of thecontacts of a relay when the relay is energized; Fig. 5 is the circuitdiagram of the setting 15 for measuring the charge collected by thetiming condenser to determinethe operating time of the relay; Fig. 6 isa symbolic operating diagram of the manipulation of the apparatus fortiming the operation of a relay when energized. Simplified 20 circuitdiagrams of the apparatus set for timing some other types of relayoperations are shown in the following figures: Fig. 7, relay withcircuit- I opening contacts when energized; Fig. 8, relay withcircuit-closing contacts when deenergized; 25 Fig. 9, relay withcircuit-opening contacts when deenergized; Fig. 10, operating time ofrelay with circuit-closing contacts when energized including summationof opening time intervals of bouncing contacts, or duration of one ormore intervals 3 with contacts open; and Fig. 11, duration of one ormore intervals with contacts closed. Figs. 12,

13 and 14 are symbolic operating diagrams representing themanipulationof the apparatus respectively for testing the operation of a relay 35.

when deenergized, for measuring the duration of one or more intervalswith contacts open, and for measuring the duration of one or moreintervals with contacts closed. Fig. 15 is a simplified circuit diagramof the apparatus set for tim- 40 ing the first only of a series ofcontact closures. Referring now more in detail to the drawings in whichlike reference characters are used to designate like parts throughout,in Fig. 1, a relay tobe tested is shown at H with a movable con- 45 tactI2 and stationary contacts 13. The timing apparatus includes a timingcondenser H, a constant-current tube l5 connectible in series withcondenser i4, and a pair of grid-controlled discharge tubes IB and H forcontrolling the charg- 50 ing of condenser I4. Switches l8 and it! areprovided for operating the apparatus to test a relay, and a switch 20 isprovided for changing the circuits of the apparatus for adjusting, relaytesting, or reading in a manner which will be explained hereinafter. Aplurality of connection posts or terminals 2| to 33, 91 and 98, adaptedto be joined by connecting links or leads are provided for reconnectingthe apparatus to make different types of time measurements or for test-'ing different types of relay operations also in a manner to beexplained. Current is supplied to the apparatus from a suitable sourcethrough terminals 34 and 35.

If desired, the range of the apparatus may be extended by connecting asecond condenser 36, preferably of different capacity, in series withcondenser I4 and either connecting a jumper from terminal 33 to one ofthe terminals 3I or 32 to short out one of the condensers or leaving thecondensers in series to obtain different values of capacity.

The constant-current tube I5 may be of any desired type, such'as athree-element vacuum tube having an anode 31, a filamentary cathode 38,and a grid 39 which may be tied to the oathode 38 or to a point 48slightly more positive.

The cathode 38 is heated by a current source 4I,.

and its emission is controlled by a rheostat 42. The tube I5 is operatedin the saturated portion of its characteristic curve so that the entirefilament emission is attracted by the anode and the current remainssubstantially constant regardless of variations in anode voltage withinthe operating range.

The discharge tubes I6 and Il may, if desired,

be of the gas or vapor-filled discharge type and are provided withanodes 43 and 44, cathodes 45 and 46, and control grids 41 and 48. Theanodes 43 and 44 are connected through resistors 48 and 58 to terminal34 of source 34--35, and the oathodes 45 and 46 are joined and connectedthrough a resistor 5| to one terminal of switch I8, which is interposedbetween resistor 5| and terminal 35 of source 34-35. The grid 41 isconnected to the common terminal of resistor 5I and switch I8, and thegrid 48 is connected through a resistor 52 to the live terminal ofswitch I8 or terminal 35 of source 34-35. Preferably, a condenser 53 isconnected between cathode 46 and grid 48 to hold grid 48 negative for aninstant and prevent tube I! from firing when switch I8 or I8 is closed.A condenser 54 is connected across the ends of resistors 49 and 58 todepress the anode potential of either tube I6 or I! when the other ismade conducting and to facilitate shifting current from tube I6 to tubeI1 and vice versa, as will be explained.

A thermionic voltmeter for measuring the charges accumulated bycondenser I4 is also provided, including a three-element discharge tube55, a plate milliammeter 56, potentiometers 51 and 58, and a comparisonvoltmeter 59, which may, of course, be calibrated directly inmilliseconds.

The switch 28 has three positions indicated by the positions I, 2 and 3of the handle 58 by means of which the movable contacts may be movedupward for position I or downward for position 3, as is apparent fromthe drawings. In order to adjust the charging current of condenser I4,the switch 28 is moved to position I or the adjusting position; beforetiming a relay, switch 28 is-moved to position 2 or the testingposition; and for reading the length of the time interval measured inthe testing position, the switch 28 is moved to position 3 or thechecking position.

When switch 28 is moved to the adjusting position I, its movable contact6| is lifted, breaking the charging circuitfrom terminal 34 and resistor58 to timing condenser I4, and contacts 82, 63 and 64 are lifted againstcorresponding stationary contacts to' form-a circuit from terminal 34 ofcurrent source 34-35 through conductor 65, resistor 58, conductor 66,contact 63, milliammeter 56, contact 62, conductor 61, contact 64,conductor 68, constant-current tube I5 (through electrodes 31 and 38),discharge tube I6 (through electrodes 43 and 45), resistor 5|, switchI8, conductor 69, to terminal 35 of source 34-35. For 10 conveniencethis circuit has been redrawn as Fig.2, showing only the portion of theapparatus included in the circuit. It will be observed that the liftingof contact 64 also shorts out the timing condenser I4 (or 36) by closinga connection 15 across the condensers through a conductor I8,

contacts II, 64, I2 and conductor I3. The desired charging-currentadjustment is obtained by adjusting the emission of tube I5 by means ofrheostat 42 until thetube passes the desired cur- 2" rent as indicatedby the milliammeter 56.

The manner of manipulating the apparatus to adjust the value of chargingcurrent is shown symbolically in Fig. 3, in which the switches I8,

I9 and 28, the rheostat 42, and potentiometer 51 15.", are representedschematically by means of theirv operating handles or control dials. Theswitches I8 and I9 are open when the handles of switches I8 and I9 aredown, and closed when their handles are up. Likewise, the positionsmarked I, 2,

and 3 are the positions of handle 68 of switch 28 for thecurrent-adjusting, testing and reading positions, respectively. Asindicated in Fig. 3, before the charging current adjustment is made,switches I8 and I9 are in their open positions, :1 and switch 28 is inposition I. The letters a, b, 0 along the bent arrow I4 which risesalong the slot for the handle of switch I8 and then points toward thecontrol dial of rheostat 42, indicate that in adjusting chargingcurrent, first switch 40 I8 is moved from the open to the closedposition (operation a), then the rheostat 42 is adjusted (operation 1)),and finally the switch I8 is returned to the open position (operation 0)Since change of position or adjustment of switches I8 45 and I9 andpotentiometer 51 is not required during the adjustment of chargingcurrent, no arrows are shown in Fig. 3 along the symbols for theseelements of the apparatus.

To time a relay with circuit-closing contacts, 50 when energized, therelay II is connected as shown in Figs. 1 and 4 with the lower blade andstationary contact I5 0f double-pole switch I9 interposed in the circuitto the exciting winding of relay I I from a source of current IS. The 5switch 28 is moved to position 2 and the circuit of Fig. 4 results, aswill now be explained.

Referring to Fig. 1, condenser I4 and constantcurrent tube I5 areconnected in series across the ends of resistors 49 and 58 in a circuitcompris- 60 ing conductor 66, contacts 6|, conductor 61, contacts l2,conductor 13, timing condenser I4 (assuming that the alternative timingcondenser 36 is shorted out by means of a jumper across its terminals 32and 33), conductor I8, contacts 1|. 5 conductor 68, anode 31 of tube I5,its cathode 38, and conductor 11. A plate circuit for thermionicvoltmeter tube 55 is formed from terminal 34 of source 34-35, throughconductor I8, contacts 63, milliammeter 56, contacts 62 and I9, anode 88of tube 55, cathode 8I to tap 82 of potentiometer 58. A grid circuit isalso formed from grid 83 of tube 55, through contacts 84 and 85, andconductors 86 and 68 to terminal 35 of source In timing the relay, afterswitch 28 has been moved to position 2 to give the circuit of Fig. 4,

switch I! is closed. This simultaneously energizes relay II by closingcontacts 13, and energlzes discharge tube It by closing contacts 81 oiswitch l8. In the specific embodiment of my invention illustrated in thedrawings, the arrangement is such that I prefer to employ at both l8 andil tubes having negative grid-control characteristics, i. e., they areconductive when the grid voltage is less negative than a given value.When switch I8 is closed, the negative charge on condenser 53 holds thepotential of grid 48 below the critical value for a sumcient length oftime to prevent tube ll from becoming conducting and permitting tube 16to become conducting.

Accordingly, current flows from terminal 34,-

through conductor 85, resistor 48, conductor 1-1, link L9, anode 43oftube It, cathode 45, resistor 5!, link L1, contact, 81 of switch i8,link La, and conductor 69 to terminal 35 oi source 34-35. Both grids 4'!and 48 are driven negative by the drop in resistor 5| so that currentcannot start in tube ll. However, current having started in time itcontinues regardless of the grid voltage in accordance with the knowncharacteristic of gas or vapor-filled discharg tubes.

The tube It has a high conductivity compared with tube i5 and when tube3 becomes conducting there is a relatively large voltage drop in re--sistor 48.. This voltage drop is impressed on timing condenser l4through resistor 58 and tube 15, and condenser I4 is charged at asubstantially constant rate controlled by constant-current tube l5 fromthe instant when switch I8 is closed.

When the relay I l operates to close-its contacts l3, however, the grid48 of tube I! is driven positive being connected to the positive side ofthe line through lead La, contacts I3, lead L4, and a resistor 88. Inconsequence, tube i'l becomes conducting, current flows from terminal 34through conductor 65, resistor 58, tube l1, resistor 5i, switch l9, andconductor 89 to terminal 35 of source 34-35. A voltage drop takes placein re-- sistor 58 and the anode potential of tube i6 is momentarilydepressed so far as to extinguish the current in tube It by reason ofthe voltage drop in resistor 591 and the negative charge which had beenbuilt up in condenser 54. Although the charge then quickly leaks offcondenser 54, tube i6 cannot regain conductivity since its grid 41 isheld negative, by the voltage drop in -resistor 5i, now maintained bythe plate current of tube ll.

As a result of the shift of currentfrom tube IE to tube I1, and fromresistor 49 to'resistor5ll, reversing the polarity of the IR drop incircuit 49, 58. l4, l5, H, the cathode of tube i5 becomes positive withrespect to its anode 31 and current cannot flow therein, therebystopping the charg= ing of timing condenser i4 and isolating it from thecircuit. The reading of milliammeter 56, indicating the plate current ofvoltmeter tube 55, is observed. The plate current may be set at asuitable value if desired by adjusting the ratio between plate voltageand grid bias of tube 55 by means of sliding tap 82 of potentiometer 58.

The magnitude of the charge collected by condenser i4 is now measured todetermine the operating time of the relay ii, the time during whichcondenser l4 was being charged. For this purpose, switch 28 (Fig. 1) ismoved to its read ing position 3. I

In order to prevent shorting the timing condenser the arrangement issuch that the contact 84 opens before the movable contacts Ii and I2close on the corresponding lower stationary contacts. 7

It will be observed thatdu'ring the opening of contact 85, the grid 830ithe tube 55 is momentarily free. During this transition period, thenegative grid bias (from 82 to 35) is removed and the plate current oftube i5 would, increase appreciably, possibly causing the milliammeter58 to swing on scale materially if it were not for the simultaneousoperation of contacts 18 and 85.

A resistor provided in series with anode 80 of tube 55 and the-movablecontact 13 is of such magnitude that when the resistor 88 is inserted inthe anode circuit by the momentary opening of contact 19, the platecurrent is limited to approximately normal value, that is, the value ofplate current with no plate resistance and with the grid bias opposed bythe drop from 82 to 35.

When the switch 20 (Fig. 1) is moved to position 3, the readingposition, the circuit shown in the simplified diagram of Fig. 5 resultsas will now be explained.

In Fig. 1 lowering movable contacts 19, ll, 12

and of switch 20 against the corresponding lower stationary contactscloses a circuit from terminal 34 of source 34--35 through conductors18, contacts 63, milliammeter 56, contacts 82, contacts 13, anode 88 oftube 55, its cathode 8i, to

tap 82 of potentiometer 58-just as in the testing position 2 of switch20, represented by Fig. 4. The grid circuit, however, is changed. 1..may

. be traced from grid 83 through contact Ii, conductor I0, condenser l4(assuming again that condenser 38 has been shorted out by a jumperbetween posts 32 and 33), conductor 13, lower contacts 12, conductor 89,lower contacts 85, conductor 38 to tap 9| of potentiometer 51. Thevoltmeter 59 is permanently connected between tap 9i and the lower ends35 of potentiometers 51 and 58.

'It will be observed that instead of being connected directly toterminal 35, grid 83 is now connected to tap ill of potentiometer 51through the timing condenser 14 (Figs. 4 and 5). The condenser I4 is soconnected that the voltage of the condenser l4 opposes the positive biasprovided by tap 9]. If necessary, the tap 9| is adjusted alongpotentiometer 5'! until milliammeter 56 gives the same reading of platecurrent as before,

indicating that the voltage of condenser l4 equals that between tap 9|and terminal 35. This voltage may be read by voltmeter 59.. Sincecondenser I4 is in'the grid circuit, no current is drawn from it and itsvoltage is accurately determined.

- The time interval to be measured or the operating time of the relay il is readily deduced from the voltage just measured of condenser i4. IfE represents the voltage developed in condenser l4 during a timeinterval to be measured, I represents the charging current inmilliamperes, C the capacity in microfarads, and T the time inmilliseconds, then C V T-E If the charging current in milliamperes I isadjusted to be numerically equal to the microfarads C of the timingcondenser, the voltage reading of voltmeter 59 will represent the timein milliseconds. For other adjustments of the charging current orcapacity to extend the operating range of the timer, a multiplicationfactor (C/I) is used. For example, if condenser 36 is made to have tentimes the capacity of condenser i4, the

range of the time may be increased ten times by short-circuitingcondenser I4 by a jumper between posts 3I and 33 and allowing condenser36 to be charged instead.

' The operations to be performed in timing a relay when energizedand'reading the length of the time interval are represented symbolicallyin Fig. 6, in which the parts of the apparatus to be operated areillustrated schematically as explained in connection with Fig. 3. Part6a of the figure represents the operation and part 6b the resetting ofthe apparatus. Referring to the Figure 6a, and following the broken line92 towards its arrow head, switch 29 is moved from position I to testingposition 2 (operation a), switch I9 is moved from open position toclosed position (operation 2;), switch 20 is moved to its readingposition 3 (operation 0), and the potentiometer 5'! is adjusted torestore the plate current reading of milliammeter 56 to its originalvalue (operation d). Alternatively, if desired, after operation 0,following the dotted line, switch I9 may first be opened, and thenpotentiometer 51 may be adjusted.

Referring to Figure 6b, following broken line 93, the apparatus is resetby opening switch I9 again (operation e) and moving switch 20 back toits current-adjusting position I (operation The charging-current must beadjusted when the timer is first placed in service, but thereafter needsonly to be checked occasionally except for readjustment to provide adiiferent time range. However, the switch 20 must be momentarily placedin position I before making a time measurement in order to dissipate thecharge existing from the preceding measurement, which would otherwiseadd directly to the measurement to be made.

Other types of time interval measurement are made and the timing ofother types of relay operations is performed in an analogous manner,having modified the connections of the apparatus with removable links orleads and in some cases rearranging the order of the operationsperformed.

To measure the time required for a normallyclosed relay to open itscontacts instead of for a normally-open relay to close its contacts, aconnecting link L5 is placed between connection posts 24 and 25, andleads L3 and L4 are attached to posts 25 and 26 as in Fig. 7 instead ofbetween posts 24 and 25 as in Figs. 1 and 4. The charging current ofcondenser I4 may be adjusted in the manner already explained. Thesequence of operation in actually timing the relay and obtaining thereading is also the same as that described in connection with Figs. 4, 5and 6, since this case also involves measuring the time required for arelay to operate after it has been energized. When switch I9 is closed,the relay II becomes energized as before and tube I6 becomes conductingas before, causing 2. voltage drop in resistor 49 which is impressed oncondenser I4 which commences being charged. Tube II now has its grid 48continually connected to the positive side of the line through theresistor 88, but it is now initially connected directly to the negativeside of the line through leads L3 and L4 and relay contacts I2 and I3,which short out resistor 52.

,When'the relay II opens its contacts, however, and removes the shortacross resistor 52, the potential of grid 49 rises to a value at whichthe tube II becomes conducting, the ratio of resistances of resistors 88and 52 being such that the required division of voltage is obtained. Asbefore, when tube I1 becomes conducting, tube I B is extinguished, thevoltage applied to the constant-current tube reverses and condenser I4ceases being charged. The voltage of condenser I4, due to itsaccumulated charge, is measured in the same manner as already explainedin connection with Fig. 5.

' In measuring the time required for a normallyopen relay to close itscontacts when deenergized, a different sequence of operations isemployed while actually testing the relay but the methods of adjustingcharging current and of reading the voltage of the timing condenser I4,in this case as in all the subsequent cases to be described, may be thesame as has already been described. Before making the test, links L1 andL2 are removed from between connection posts 21 and 29 and between 28and 39 and placed between posts 29 and 3 I and between 30 and 32. LeadsLa and L4 are connected to posts 24 and 25, respectively, and link L5 isremoved from between posts 24 and 25.

The test is begun with switch 29 in position 2 and switch I9 closed(Figs. 8 and 12a). First, switch I8 is closed (operation a, Fig. 12a),and then switch I9 is opened (operation b). Referring to Fig. 8, whenswitch I8 is closed, tube I6 becomes conducting and charging currentcommences to flow through tube I5. Condenser I4 cannot begin charging,however, until the short across it through switch blade 81 is removed byopening switch I9, at which time relay II is deenergized by theseparation of contacts I5 and commences to operate. the relay operationand the closing of its contacts I3, grid 48 is driven positive, causingcurrent to be shifted from tube IE to tube I1 and stopping the chargingof condenser I4. The reading is then taken (operations 0 and d, Fig.12a) and the apparatus is reset for another test (operations e and ,f,Fig. 12b) For observing the time required for a normallyopen relay toopen its contacts when deenergized.

the removable links and leads are placed as shown in Fig. 9; L1 betweenconnection posts 29 and 3|; L2 between 30 and 32; L5 between 24 and 25;leads L3 and L4 connected to 25 and 26. The sequence of operations is asdescribed just above and shown in Fig. 12. The operation of the circuitwill be apparent from the, explanation of partially analogous circuits,Figs. 7 and 8. When switch I8 is closed, tube I6 starts conducting; whenswitch I9 is opened, relay II is deenergized and condenser I4starts-charging; and when contacts I3 open, grid 48 is driven positive,communicatingthe tubes I6 and I1 and condenser I4 stops charging.

It is apparent, that in the cases previously described bouncing ofthe-contacts after the original closing or opening is without efiect onthe operation of the apparatus. Once the contacts I3 have operated tomake grid 48 positive and tube I'I conducting, grid control of tube I Iis lost and it continues to conduct in the known manner ofgrid-controlled gas or vapor discharge tubes. Resumption of charging ofcondenser I4 is prevented and the relay operating time for onlytheoriginal closing or opening operation is measured. However, if it isdesired to take into ac- Upon the completion of tying the circuit shownin Fig. 4 to produce that shown in Fig. 10; that is, link L0 is removedfrom between posts 22 and 29 and leads L: andLi' are connected to posts2| and 22. The sequence of operations in manipulating the apparatus isas shown in Fig. 6. Comparing Fig. 10 with Fig. 4. it will be apparentthat the distinction in opera tion of the apparatus is that in Fig. 10whenever contacts I! reopen, the circuit through resistor 58 toconductor 69 is broken and current is reestablished in tube l6 insteadof continuing to flow through tube I! as in Fig. 4. Consequently,charging current flows in condenser ll during the time that contacts itare open and the measurement obtained is the summation of closing timeand open time intervals. Obviously, the circult of Fig. 10 may be usedgenerally for measuring the duration of one or more intervals that apair of contacts l3 are open. The initial positions of the switches andthe sequence of operations would-be as indicated in Fig. 13.

For measuring the operating time of a relay closing when deenergizedincluding the summation of opening time intervals for bouncing contacts,the connection of Fig. 8 is modified as indicated in connection withFig. 10, that is, link L6 is removed from between posts 22 and 23 andleads Lo and L4 are connected to posts 21 and 22. The sequence ofoperations in manipulating the apparatus is as shown in Fig. 12 and asexplained in connection with that figure. For the reasons stated in theprevious paragraph, the measurement includes the summation of open timeintervals.

Fig. ll'represents the arrangement of the apparatus used when it isdesired to-measure the duration of one or more intervals that a pair ofcontacts, such as l3, remains closed. Links L1,

1a and L6 have been removed from between connection posts 29 and 3|, 38and 32, 22 and 23, respectively, and leads L3 and L4 have been connectedto posts 21 and 28, respectively. Manifestly, condenser I4 is chargedonly during the periods that a circuit is closed through contacts I3 andtube l6 conducts current. Fig. 14 represents the sequence of operatingduring the ma- 'nipulation of the apparatus.

Another type of measurement which the extreme flexibility of myapparatus permits is the measurement of the time duration of the firstonly of a series of contact closures. To make a measurement of thistype, the apparatusillustrated in Fig. 1 is connected to include atransformer 94 and a voltage source 95, forming the circuit illustratedin Fig. 15. The link L9 is removed from between posts 91 and 98 and thecontactsl3 of the relay II are connected in series with the primarywinding 96 of the transformer 94 to the connection posts 91 and 98 bymeans of the leads Lo and L4. The secondary winding 99 of thetransformer 94 is connected in series with the voltage source toconnection posts Hand 28 by means of leads L! and La. The connectionsare such that the negative side of the voltage source 95 is connected tothe grid 48 of tube 11, and the terminals of transformer windings 96 and99 connected to posts 98 and- 25 have the same polarity.

In measuring the time duration of the first of the series of closures ofcontacts IS, the switch.

cult of tube It is open through contacts I: and the voltage source 95maintains a negative potential on the grid 48 of discharge tube I1. Upona closure of the contacts 12 and I3, the anode circuit of tube I8 isclosed and tube I9 begins to 5 conduct. As explained in connection withthe previous measurements, the charging current begins to flow into thetiming condenser l4 upon the initiation of a discharge in tube Hi. Thecurrent impulse through the primary winding 99 of .transformer 94 causedby the closure of contacts l3 produces an induced voltage in secondarywinding 99 but the polarity is such that the grid 48 of tube I1 ismerely driven further negative by 15 this induced voltage and theinduced voltage .has no effect on the discharge tube I! which ismaintained non-conducting by thecurrent flowing in resistor 5| fromdischarge tube l6, which produces a negative bias on grid 48 oftube I1.

Upon the. opening of the contacts l2 and I3,

the current through primary winding 98 of transformer 94 is interruptedand a voltage of opposite polarity is induced in transformer secondary99, causing the grid 48 of tube H to become positive with respect to itscathode 46 and making the tube II conducting. The circuit to tube l6having been interrupted, the polarity of the voltage acting in thecircuit of the timing condenser is reversed, as in the previousexamples, and the charging of the condenser 14 ceases. should thecontacts l2 and I3 be reclosed subsequently, tube IE will remainnon-conducting owing to the fact that the current flowing through tubel1 and resistor 5| biases the grid 41 of 5 tube l6 negatively andprevents the reestablishment of a discharge in tube I6. The chargeaccumulated in timing condenser I4 is measured, as explained inconnection with the previous examples, by moving switch 28 to position3, adjusting the potentiometer 51, and taking the reading of milhammeter58 and voltmeter I9.

It will be seen, therefore, that the connection of Fig. 15 permitsmeasuring the duration of the first of a series of contact closuresirrespective 5 of the number of reclosures which may occur.

In accordance with the provisions of the patent statutes, I havedescribed apparatus which I now consider to represent the bestembodiment ofmy invention and certain methods of operation embracedtherein for the purpose of explaining its principle and showing some ofits applications but it will be obvious to those skilled in the art thatmany modifications and variations are possible and I aim, therefore, tocover 55 all such modifications andvariations as 'fall within the scopeof my invention which is defined in the appended claims.

WhatI claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. An electric device for timing relay operations comprising acondenser, means adapted to charging said condenser at a substantiallyuniform rate, means for starting and stopping the charging of saidcondenser simultaneously with 65 the beginning and end, respectively, ofa relay operation to be timed, and means responsive to the chargeaccumulated by said condenser.

2. A device for timing relay operations comprising a condenser, meansadapted to charging 70 said condenser at a substantially uniform rate,means for modifying the connections of said device to permit measurementof both closing and opening times of normally-open and normallyclosedrelays, means for starting and stopping the 75 charging of saidcondenser simultaneously with the beginning and end, respectively, of arelay operation to be timed, and means responsive to the chargeaccumulated by said condenser.

3. Apparatus for timing the operation of an electrical relay having anenergizing winding and a pair of relatively movable contacts adapted toopen and close an .electrical circuit, which timdenser,

ing apparatus comprises a condenser, means adapted to charging saidcondenser at a substantially uniform rate, means for starting andstopping the charging of said condenser, adjustable means for connectingthe contacts of the relay being timed to said charge-starting andstopping means, said connecting means being adapted to setting theapparatus for measuring opening and closing times of normally-open andnormally-closed relays, and means for determining the charge collectedby said condenser.

4. A method of timing the operation of a relay having an energizingwinding in a relay-operating circuit and having a pair of relativelymovable contacts, which comprises simultaneously initiating an operationof said relay through control of said operating circuit and causing acondenser to start charging through a constant-current unidirectionalcircuit, causing the polarity of the supply to said last mentionedcircuit to be reversed simultaneously with the operation of saidcontacts, and determining the voltage of said condenser.

5. The method of timing the operation of an electrically operatedcontact controlling relay which consists in simultaneously initiatingthe operation of said relay and starting to charge a condenser at aconstant rate, stopping the charging of said condenser simultaneouslywith the operation of said relay and measuring the initiation of suchrelay operation and the completion of the relay operating movement andthen measuring the charge on said condenser.

7. A device for timing relay operations which comprises a unidirectionalconstant-current circuit including a condenser, a direct current sourceof charging current supplying said circuit, means for connecting saidcondenser circuit to said source in a direction normally to causecurrent to fiow in said circuit at the beginning of a relay operation,means for reversing the polarity of said source upon the completion ofsaid operation, and means for determining the quantity of' chargecollected by said condenser.

8. -A timer comprising in combination, a cona constant-current rectifierin series therewith, a direct current voltage source connected to saidcondenser and said rectifier in a direction normally to cause current toflow in said rectifier, means for energizing said voltage source at thebeginning of an operation to be timed, means for reversing the polarityof said voltage at the conclusion of the operation, and means fordetermining the amount of electric charge accumulated by said condenserduring said operation.

9. A timer comprising in combination, a condenser, a thermionic tubehaving an anode and a cathode and operated in the saturated portion ofits characteristic curve in which the entire emisplied to the electrodesof said tube, a direct ourrent source 01 voltage to which said condenserand said tube are connected in series, the connections a being such asnormally to tend to cause current to fiow in said tube, means forenergizing said volt-- 5 age source at the beginning of a time intervalto bemeasured, means for reversing the polarity of said voltage at theend of the time interval, and means responsive to the amount of electriccharge accumulated by said condenser during said time w interval.

10. A timer comprising in combination, a source of current, a pair ofdischarge tubes, each having an anode, a cathode, and a control grid,and being connectible in parallel to said source of current, 1 separateresistors connected in series with the anodes of said tubes, a timingcondenser and a constant-current rectifier connected in series betweenthe anodes oi. said tubes, a second condenser connected between theanodes of said tubes, means for closing a circuit from said currentsource to said tubes at the beginning of a time interval to be measured,thereby initiating a discharge current in one of said tubes, giving riseto a potential difierence in one of said series resist- 25 ors and inthe circuit of said constant-current rectifier and said timing condenserand giving rise to a charging current in said condenser, means formomentarily at least maintaining the control grid of the other of saidtubes at too low a potential to 30 permit the tube to become conductingat the beginning of the time interval, means for raising the potentialof the control grid of said latter tube at the conclusion of the timeinterval, thereby making the tube conducting and shifting current from35 the former of said tubes to the latter and from one of said-seriesresistors to the-other, whereby the potential diflerence between. saidanodes and in the circuit of said rectifier and said timing condenser isreversed, terminating the'charging of 4 said condenser.

11.- A timer comprising in combination, a source of current, a pair ofdischarge tubes, each having an anode, a cathode, and a control grid, aresistor connected between the anode of one of said tubes 45 and oneside of said current source, a second resistor connected between theanode of the other of said tubes and the same side of said currentsource, a constant-current rectifier and a timing condenser connected ina cross-circuit in series 50 between the anodes of said tubes, a secondcondenser connected between said anodes, a switch between the other sideof said current source and the cathodes of said tubes arranged to beclosed at the beginning of a time interval to be measured, 55 therebyinitiating a discharge in the first oi. said tubes, a second switchadapted to connect the control grid of the second 01' said dischargetubes to the anode side of said current source and arranged to be closedat the end of a time inter- 60 val to be measured, thereby making thelatter discharge tube conducting, shifting current there: to from thefirst of said tubes and reversing the potential difi'erence in saidcross-circuit, whereby said timing condenser receives charging current65 only during a time interval to be measured.

12. A timer comprisingin combination, a pair of capacitatively-coupledparallel circuits including grid-controlled discharge tubes and having across-connection including a rectifier and a tim- 70 'aoamoe 7 tentialof the tube in the second of said parallel circuits at the end of a timeinterval to be measured, thereby making said second-tube'conduct- 'ing,depressing through said capacitative coupling the voltage acting onthetube in the first of said parallel circuits until said tube isdeenerzized, shifting the current between said parallel circuits toreverse the voltage in said cross-circuit and terminate the charging ofsaid condenser.

13. A device for timing the opening of the contacts of a relay when therelay is energized which comprises a pair of parallel circuits includinggrid-controlled discharge tubes and having a cross-connection includinga rectifier and a timing condenser, means for simultaneously energizingsaid relay and one of said tube circuits, thereby giving rise to avoltage in said cross-circuit causing said condenser to start receivinga charge, a voltage divider having a tap determining the grid potentialof the tube in the second tube circuit, one side of said voltage dividerbeing initially shortcircuited by the contactsof the relay, whereby thegrid potential of said second tube is initially held below the point atwhich said tube becomes conducting, and the opening of the contactserves to raise the grid potential of said tube, causing it to becomeconducting, to shift the current between said parallel tube circuits, toreverse the voltage in said cross-circuit, and to terminate the chargingof said condenser.

14. A device for timing the operation of a relay when deenergizedcomprising a pair of parallel circuits having a cross-connectionincluding a rectifier and a timing condenser in series, one of saidparallel circuits initially carrying current and producing a potentialdifierence in said crosscircuit tending to cause a charging of saidcondenser, means initially maintaining said relay energizedandshort-circuiting said condenser to prevent it from receiving chargingcurrent, said means being adapted simultaneously to deenergize saidrelay and to remove the short from said condenser, permitting chargingthereof, means for shifting the current from the initially conductingcircuit to the other parallel circuit upon the operation of said relay,thereby reversing the potential difierence in said cross-circuit andterminating the charging of said condenser.

'15. A device for measuring the summation of the original operatingtime'of a circuit-closing relay having bouncing contacts and the timeduring which the conacts may be open again, which comprises, incombination with a source of current, a tube circuit supplied therebycomprising a resistor and a discharge tube in series, a second circuitin parallel with-said tube circuit including a second resistor in serieswith the contacts of the relay being tested, a cross-circuit betweensaid firstmentioned circuits including a timing condenser and arectifier in series, capacitative coupling between said first mentionedcircuits, and

means for simultaneously starting the operation of the relay and closingsaidtube circuit, there- 5 by energizing said circuit and giving rise toa voltage in said cross-circuit causing .sald condenser to startreceiving a charge, whereby said condenser continues receiving a chargeuntil the relay contacts close causing currentto flow in 1 said secondcircuit, depressing through said onpacitative coupling the voltageapplied to said tube below. that at which current can continue to flowin said tube circuit,-reversing the voltage. in said cross-circuit tostop the charging of said 15 condenser while the relay contacts areclosed, but permitting current to fiow again in said tube circuit and insaid condenser-charging cross-circuit during such time as the relaycontacts may again be open. 1 '20 16. A device for timing the first ofseveral repeated closures of a pair of contacts which comprises a pairof parallel circuits including gridcontrolled discharge tubes and havinga crossconnection including a rectifier and a timing condenser, saiddischarge tubes each having an anode, a cathode, and a grid, atransformer having primary and secondary windings, a source of biasingpotential, and means for reversing the polarity of voltage acting insaid cross-circuit when current shifts from one parallel circuit to theother,

the primary winding of said transformer and said contacts beingconnected in series with one of said discharge tube circuits and thesecondary winding of said transformer and said source of biasingpotential being connected between the cathode and control grid of thedischarge tube in the other of said parallel tube circuits whereby theinitial closing of said contacts closes a circuit through the firstmentioned of said discharge tubes and causes current to flow in saidcrosscircuit starting the charging of said timing condenser, and theinitial opening of said contacts induces a voltage in the secondarywinding of said transformer impressinga positive potential on thecontrol grid of said second mentioned discharge tube causing it tobecome conducting and to commutate said first mentioned discharge tube,reversing the potential in said cross-circuit and terminating thecharging of said timing con- 5 denser, said first mentioned dischargetube having its grid connected to be negatively biased by the resistancedrop due to current flowing in the, circuit of said second mentioneddischarge tube, preventing the first tube fromagain becoming conductingin response to subsequent contact closures.

MAURICE E. BIVENS.

commune oi CORRECTION.

v Patent No. 2,021,765. November 19, 1935.

MAURICE E. BIVENS.

- It is hereby certified that error appears. in the printedspecification of the above numbered patent requiring correction asfollows: Page 4, second column,

line 56, for the syllable "communicat-" read commutat-;page 7, firstcolumn, line 53. claim 15, for "conacts" read contacts; and that thesaid LettersPatent should be read with these corrections therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealed this 7th day of'January. Ar D 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents.

CERTIFICATE or CORRECTION.

. Patent No. 2,021,766. November 19, 1935.

MAURICE E. BIVENS.

- ll is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 4,second column, line 56, for the syllable "communicat-" readcommutatqpage 7, first column, line 53. claim 15, for "conacts" readcontacts; and that the said Letters Patent should be read with thesecorrections therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 7th day of January. A. D. 1936.

Leslie Frazer (Seal) v Acting Commissioner of Patents.

